Is there association between Glutathione S Transferases polymorphisms and cataract risk: a meta-analysis?

Background: Glutathione S transferase (GST) polymorphisms have been considered as risk factors for age-related cataracts, but the results remain controversial. In this study, we have performed a meta-analysis to evaluate the association between polymorphisms of GSTM1 and GSTT1 and cataract risk. Methods: Published literature from PubMed and other databases were retrieved. The case-control studies regarding the association between GSTM1 or GSTT1 polymorphism and cataract risk were included. Pooled odds ratio (OR) and 95 % confidence interval (CI) were calculated using random-or fixed-effects model. Results: Fifteen studies on GSTM1 (3,065 patients and 2,105 controls), and nine studies on GSTT1 (2,374 patients and 1,544 controls) were included. By pooling all the studies, GSTM1 null polymorphism was not associated with cataract risk, and this negative association maintained in subgroup analyses. However, GSTT1 null polymorphism was significantly associated with increased risk of posterior subcapsular (OR, 1.42; 95 % CI, 1.04-1.94) but not other subtypes of cataract. Stratified analyses demonstrated an association of GSTT1 null genotype with increased risk of cataract in Asian (OR, 1.44; 95 % CI, 1.14-1.83) but not Caucasian populations. In addition, seven pooled studies showed no association of cataract risk with the combined GSTM1 and GSTT1 null genotypes. Conclusions: This meta-analysis suggests that GSTT1 null polymorphism is associated with increased risk of posterior subcapsular cataract. Given the limited sample size, the association between GSTT1 null polymorphism and cataract risk in Asian awaits further investigation.